Walked out this morning and realized that it was too tall to build a door with the steel studs I've got so I had to spend a damn hour with an angle grinder cutting a foot off the height. I think it's much more reasonably sized now anyway but annoying nonetheless.

55,000 btu is crazy for something only going to 200°. You're also setting yourself up with hot spots and cold spots by running propane in a box. I know that guy's thread says he wants propane to save cost over electric, but you're going to have to vent off 80% of the energy. With ceramic fiber insulation, like a decent oven has, you shouldn't need over a 1000 btu per cubic foot and honestly far less than that. I can get a 10 cubic foot kiln to 2300° with 25,000 btu.

Also: You'll have to be careful to avoid a reduction environment, which will effect color and cure.

I was wondering why propane, I didn't read the article. Take you guts out of the home oven and re-use those. It will heat up that larger box fine to 200 and it has the temp sensor and vent controls etc all in it.

55,000 btu is crazy for something only going to 200°. You're also setting yourself up with hot spots and cold spots by running propane in a box. I know that guy's thread says he wants propane to save cost over electric, but you're going to have to vent off 80% of the energy. With ceramic fiber insulation, like a decent oven has, you shouldn't need over a 1000 btu per cubic foot and honestly far less than that. I can get a 10 cubic foot kiln to 2300° with 25,000 btu.

Also: You'll have to be careful to avoid a reduction environment, which will effect color and cure.

it needs to go to ~700 to cure ceramic coating for turbos heads and downpipes etc. 350-450 for powder.Still overkill, but it will get to temp quickly and propane is cheap. Under a buck an hour to run. It's on a PID so it only runs when it needs to so no real waste other than venting which I believe will be minimal, we shall see.

My shop is maxed out on electricity, we run a robotic welder, a cnc plasma, a cnc mill, a manual mill, a press brake, a brush sander and three manual welders already (on residential power, don't tell my electric company! And that doesn't include the 150+HP running in the wood shop lol) and there's no more overhead for electricity unfortunately.

Insulation is rockwool (mineral wool) good to 2500 or so. As for hot and cold spots, the heater used has a fan, so there is circulation whenever it is running which *should* help with that.

I'm certain lower btu would do the job, but I'd rather overdo it and have it run less often than have to wait 45 minutes for it to get to temp. There are a lot of more commercial builds of similar ovens running 125K + btu.

I know you know your shit and would probably build a much better one than I am, but this oven is tried and true and a bunch of people use them without issue even in production shops.

The guy who coats our stuff now has a gas oven with more BTU than I can fathom. It looks like a jet engine with the afterburner going. His oven is about 12x12x24'

As for reducing environment, you're probably right but I've been coating in a propane oven for years without a problem, and that's without any circulation just straight burner. I'd prefer electric, but just no more power to run it.